Conventional jaw chucks as associated with rotary machine tools, such as lathes, employ a rotatable chuck housing which mounts thereon a plurality of radially displaceable jaw carriers, and these in turn removably mount jaws which are adapted for gripping a workpiece. The jaws assume many shapes and sizes, and hence are interchangeably mountable on the jaw carriers to facilitate use of the chuck in conjunction with a wide variety of workpieces. One conventional mounting technique for removably securing the jaws to the jaw carriers involves the use of threaded fasteners, specifically screws or bolts. Such arrangements, however, are time consuming when changing of the jaws is desired, increase the size, mass and complexity of the jaw arrangement, and often result in structures which reduce the rigidity of the jaw assembly but increase the undesired centrifugal force effect.
In an attempt to facilitate the mounting of the jaws on the carrier assemblies, several arrangements have been developed employing a carrier assembly having main and auxiliary carrier members which are relatively movable with respect to one another to facilitate the mounting or removal of the jaw. Most of these arrangements, however, have still possessed features which have resulted in structural and operational complexities.
One such arrangement is illustrated by U.S. Pat. No. 3,868,120 (Blaettry). This patent illustrates a main jaw carrier having an auxiliary carrier slidably mounted thereon. In this arrangement, however, all of the opposed surfaces of the jaw carriers must be rigidly joined together to permit proper utilization of the arrangement, and hence this restricts the changing of the jaws.
Another arrangement is illustrated by U.S. Pat. No. 3,219,356 (Wilterdink) which discloses a rotary cam for locking the upper and lower jaw carrier portions together, although the joining of the carrier portions is through interfitting serrated surfaces. This type of arrangement increases the manufacturing cost and decreases the efficiency of the apparatus as regards its convenience of use.
Other arrangements of this general type are disclosed by U.S. Pat. Nos. 3,833,232, 2,667,358, 3,679,221 and 4,352,500. The arrangements of these latter patents involve complex structural and functional arrangements which hence minimize their desirability.
Accordingly, this invention relates to an improved jaw carrier arrangement for permitting rapid and efficient removing and/or mounting of a top jaw. The improved jaw carrier arrangement is believed to possess a highly improved and more desirable structural and functional arrangement so as to facilitate both economical manufacture and efficient utilization thereof.
In the improved jaw carrier arrangement of this invention, there is provided a main jaw carrier which slidably supports thereon an auxiliary or locking carrier. The main and auxiliary carriers are radially spring-urged apart, with the auxiliary carrier being radially outermost and slidably supported on the main carrier. A locking cam is rotatably mounted on the main carrier for locking the auxiliary carrier in an outer position in which position the carriers are adapted to rigidly support a jaw thereon. The auxiliary and main carriers have oppositely directed dovetail grooves to facilitate rapid but secure engagement with opposed grooves formed on the jaw. The locking cam can be rotated into a release position wherein the auxiliary carrier can be easily manually displaced inwardly in opposition to the spring to facilitate mounting or removing of the jaw. Release of the manual pressure on the auxiliary carrier results in the spring urging the auxiliary carrier outwardly to securely grip the jaw by the opposed dovetail guides, and thereafter the locking cam is rotated to engage the auxiliary jaw carrier and prevent inward movement thereof.
The improved jaw carrier arrangement, as aforesaid, permits a jaw to be rapidly mounted on or removed from the assembly, and the rotational centrifugal force imposed on the auxiliary carrier acts through the dovetail guide to create a more secure gripping of the jaw. This arrangement also permits the jaw, and its point of engagement with the workpiece, to be positioned more closely adjacent the front of the chuck housing and hence closer to the main spindle bearings so as to provide improved overall rigidity. The arrangement also possesses a limiting stop which cooperates between the auxiliary and main carriers for maintaining the auxiliary carrier in an outermost limit position, due to the urging of the spring, when the jaw is removed from the carrier assembly.
Other objects and purposes of the invention will be apparent to persons familiar with structures of this type upon reading the following specification and inspecting the accompanying drawings.